Dry cell.



I. RUDOLPHS.

DRY CELL.

APPLICATION FILED NOV. 15, I911.

1 9 84,13. Patented May 23, 1916.

MW 5 ugh Attorney.

I JOHN R UDOLPHS, OF HENRIKSDAL, SWEDEN.

1m: can.

Specification of Letters Patent.

Patented May 23,1916.

Application filed November 15 1911. Serial No. 660,444.

such cells in such a manner as to permit the escape of the gases formed at the positive electrode and contributing to a rapid decrease of the current, viz., to the polarization of the battery, but at the same time to prevent the escape of moisture from the pasty electrolyte of the battery and thus to prevent, as far as possible, its drying.

As Well known, it is of importance-for the activity of dry battery cells to maintain the electrolytic body of it in a moist condition. In the usual dry battery cells a continuous evaporation of the moisture of the said body takes place through the pores of the carbon electrode which is exposed to the outer air.

'For that reason, the pasty electrolyte soon becomes dry and the activity of the battery ceases. Foravoiding this inconvenience, ac

cording to the present invention, thepores of the carbon electrode wholly br partly are filled with a hygroscopic liquid, for instance a solution of a hygroscopic salt. The pores of the carbon electrode are filled with hygroscopic liquid by soaking the electrode in said liquid. This hygroscopic liquid prevents the continuous evaporation through the pores of the carbon electrode of the moisture from the electrolyte, but permits the escape ofthe gases formed in the'interior of the bat- 'tery.

The invention may be applied to any lmown form of dry battery cell which is provided with a porous electrode exposed to the air. Such a dry cell is illustrated by way of ample in the accompanying drawing, in which the figure is a sectional view therethrough.

In the cell shown in the drawing a zinc electrode a is surrounded in the usual man-,

ner with a paste electrolyte 12 contained in a porous electrode 0 which is exposed to the air while the pores of the said electrode are filled with hygroscopic liquid, for example of calcium chlorid.

During the activity of the battery, gases,

as well known, are formed in the interior of it. When these gases obtain a certain pres-" sure they escape through the pores of the carbon electrode an carry away with them some evaporated moisture from the body of the electrolyte. These escaping gases cannot expel the hygroscopical liquid from the pores,

of the carbon electrode because the said liq-' uid is retained in the pores by'the capillary action of the carbon.

During the intervals of rest between the periods of activity of the element no gases are formed. During that time the hygroscopic liquid in the-pores of the carbon electrode acts as a liquid seal and prevents the escape of moisture from the electrolyte. In this manner the period of life of the battery cell becomes much longer than that of'the usual dry battery cells in which the moisture of the electrolyte can always freely escape through the bores of the carbon.

It being important that the sealing liquid in the pores of the carbon electrode should not evaporate, a hygroscopic liquid is used as sealing liquid. The losses arising in this liquid from its evaporation at thesurface of the carbon electrode which is in contact with the outer air are compensated in the following manner. The gases formed in the battery cell, viz., hydrogen and ammonia first form a layer of gas on the surface of the carbon electrode facing the zinc electrode and then move by and by through the carbon electrode pores filled with hygroscopic liquid, which liquid thereby becomes saturated with the sald gases. On account of the constant effiux of gas from the interior of the battery cell part of the gas and especially ammonia absorbed by the hygroscopic fluid during the activity of the battery cell escapes at the surface of the carbon electrode which is exposed to the outer air, and water is deposited on the carbon electrode; which is absorbed by the hygroscopic liquid. In this manner the quantity of liquid in the pores of the carbon electrode is kept practically uniform.

What I claim and desire to secure by Letters Patent of the United States is A dry battery cell comprising a pluralitv ofelectrodes, one of said electrodesfbeing In testimony whereof I have signed my porous, andpasty electrolyte, said porous name to this specification in the presence of electrode being in contact With the atmostwo subscribing Witnesses. phere and impregnated with a hygroscopic JOHN RUDOLPHS.

5 liquid whereby moisture is absorbed from Witnesses:

the atmosphere therethrough to prevent the BIRGER NORDFELDT, drylng out of the electrolyte. HiLMA TELANDER. 

